Synergistic physic-chemical pretreatment of lignocellulosic sugarcane bagasse via freezing and alkaline processes

Abstract EN

This study focuses on employing a hybrid pre-treatment approach for lignocellulosic sugarcane bagasse (SCB) as a major problematic solid waste.

the applied technique depended on SCB physical pre-treatment via freezing, followed by chemical hydrolysis using alkaline hydrogen peroxide (AHP) and enzymatic hydrolysis.

the changes occurred in macrostructure and the entire lignocellulosic compounds during the pre-treatment stages were evaluated.

freezing pre-treatment resulted in relatively low glucose yield and saccharification ratio at -20 °c for 2 h of 307.52 mg / gm native SCB and 48.5%, respectively.

further ahp pre-treatment was performed for the frozen-pre-treated SCB at -20 °c and 2 h with assistance of box-behnken design response surface methodology (RSM).

the investigated key parameters were h2o2 concentration (3, 5.5 and 8 %v/v), temperature (25, 42.5 and 60 °c) and pre-treatment duration (1, 3 and 5 h).

the results revealed that the statistical modelling was able to predict the response of glucose yield and TRS production with r2 = 0.8221 and 0.8814, respectively.

applying the optimization tool of RSM, the optimum predicted values of glucose yield and TRS production were (886.51 mg/gm native SCB and 1.44 mg / ml), respectively; confirmed by the experimental analysis (898.5 mg / gm native SCB and 1.32 mg / ml), respectively.

the coincided saccharification ratio was 97.5%.

these results were obtained at H2o2 of 3 % (v / v), 56.93 °c and 1 h which were 4.32 and 2.01 times higher than that obtained during the freezing pre-treatment phase for glucose yield and saccharification ratio, respectively.

the results are higher that obtained in the literature for SCB with 2% (v / v) H2o2 at 30°c for 8 h.

therefore, the AHP following freezing pre-treatment proved the efficient break down of esterified linkage in the lignocellulosic matrix and DE acetylation of hemicellulose during the process.